Although there is no reliable evidence that exercising reduces the curve, intuitively we know that exercising is good.
It can reduce pain, make you feel much better and it can even improve (from my own experience) your back aesthetically.
Yoga, Pilates and other hugely popular techniques strengthen your muscles, improve your posture and it is our duty to make use of them. Of course for those with severe curves, mobility restrictions and scoliosis combined with other problems, it is vital to consult with specialist any exercising routine you want to start.
My personal favourite is Structural Yoga Therapy (see the book section of the site) but I tried to assemble information about places, people and therapies for you to choose from. The list is growing everyday, please, send me comment if you have something to add.